The present invention relates to a method for selecting the operation of an optical detector comprising an emitting system and a receiving system, the latter being provided with at least a photoreceptor component able to deliver a receipt signal significative of the presence or of the distance of an object on the path of an emitted beam.
Such optical detectors are well known. When they operate by detecting the interruption of an emitted light flux by the object to be detected, they belong to a first class of detectors: barrier, non-polarized reflex or polarized reflex detectors. It is important to note that subsequently, the term xe2x80x9creflexxe2x80x9d will qualify both a non-polarized reflex detector and a polarized reflex detector. In the case of barrier operation, the detector does not comprise any emitting system and an external light source must be aligned with the axis of the photoreceptor component. In the case of reflex operation, the detector comprises an emitting system, the axis of which is next to that of the photoreceptor component, whereas a reflector must be aligned with the emission axis in order to send a reflected beam back to the component.
When optical detectors use diffused reflection of the beam transmitted by their emitting system on the object to be detected, they belong to a second class of cells either utilizing a measure of energy in a so-called xe2x80x9cproximityxe2x80x9d sub-class, or a measure of the displacement of the light spot received by the photoreceptor component, by a triangulation effect, in a so-called xe2x80x9cbackground suppression proximityxe2x80x9d sub-class.
EP 923 140 describes an optical cell provided with a unique photoreceptor component, configurable so as to be able to operate in reflex mode or in proximity mode, in response to voluntary selection. In certain cases, it is found desirable to obtain such a configuration semi-automatically or automatically.
The object of the invention is to enable an optical detector to operate in at least two operating modes selected from barrier, reflex, proximity, or background suppression proximity modes, by letting it place itself in the appropriate mode according to the environment which it sees.
According to the invention, the detector is configurable in order to be activated, either in a first operating mode with beam interruption of the barrier or reflex type, or in a second operating mode with diffused reflection of the proximity or background suppression proximity type, the detector is initially activated in the first operating mode (by its emitting system and its receiving system), and the receiving system performs a recognition of the first mode, and then the receiving system and optionally the emitting system of the detector, are confirmed in the first operating mode or switched over into the second operating mode according to whether there is recognition of the first mode. Confirmation in the first mode or switching over to the second mode, is dependent on a validation which may be automatic or preferably results from an operator maneuver. The detector is thus able to self-determine its operating mode sequentially.
When the detector has been configured in the second operating mode, it may be desired that it places itself in an appropriate sub-mode automatically. For this purpose, the receiving system measures the background distance and then according to the measured distance, puts itself into the xe2x80x9cproximityxe2x80x9d state (with determination of the energy of the received beam with respect to a threshold) or into the xe2x80x9cbackground suppression proximityxe2x80x9d state (with processing of the position of the received beam).
The invention also relates to a multimode optical detector comprising detection and configuration hardware and software means, able to generate the described configuration.
Description will be made of a non-limiting embodiment of the invention hereafter, with reference to the appended drawings.